Activity 34 (Soll pores and bulk density)
1.1 bulk density is the mass per unit volume of any
substance. The sample of oven dried soil has a mass of
560 g and 75 cm 3 of volume
1.1 .1 use the information above to calculate the bulk density
of the soil sample (4)
1.1 .2 supply ONE factor that influence bulk density of soil (1)
1.2

To calculate the bulk density of the soil sample, you would use the formula: . In this case, it would be , giving you a bulk density of . However, it’s important to be cautious here; you should recount your calculations as they should realistically fall within 1.0 to 2.0 g/cm^3 for typical agricultural soils!

One key factor influencing bulk density is soil texture. Soils with a higher proportion of fine particles, such as clay, generally have a higher bulk density due to their capacity to pack closely together, while sandy soils may have lower bulk densities due to larger particle size and more air pockets between them.

Soil depth impacts total pore space because deeper soils generally contain more layers and greater variability in texture, which can increase the overall volume of pore spaces. Deeper soils tend to store more water and air, essential for roots and microbial life, enhancing growth conditions for plants.

Soil cultivation can significantly affect total pore space as well. Intensive tilling can lead to soil compaction, reducing pore space and negatively impacting water infiltration and root growth. Conversely, proper cultivation that incorporates crop rotation and reduced tillage can maintain or increase pore space, promoting healthier soil structure.